Devices, systems, and methods for accessing the epicardial surface of the heart

ABSTRACT

Devices, systems, and methods for accessing the internal and external tissues of the heart are disclosed. At least some of the embodiments disclosed herein provide access to the external surface of the heart through the pericardial space for localized delivery of leads to the heart tissue. In addition, various disclosed embodiments provide devices, systems, and methods for closing a hole in cardiac tissue.

PRIORITY

The present application is related to, and claims the priority benefitof, International Patent Application Serial No. PCT/US2008/053061, filedFeb. 5, 2008, which is related to, claims the priority benefit of, andin at least some designated countries should be considered acontinuation-in-part application of, International Patent ApplicationNo. PCT/US2007/015207, filed Jun. 29, 2007, which is related to, andclaims the priority benefit of, U.S. Provisional Patent Application Ser.No. 60/914,452, filed Apr. 27, 2007, and U.S. Provisional PatentApplication Ser. No. 60/817,421, filed Jun. 30, 2006. The presentapplication also claims the priority benefit of International PatentApplication No. PCT/US2007/015207, filed Jun. 29, 2007, and U.S.Provisional Patent Application Ser. No. 60/914,452, filed Apr. 27, 2007.The contents of each of these applications are hereby incorporated byreference in their entirety into this disclosure.

BACKGROUND

Ischemic heart disease, or coronary heart disease, kills more Americansper year than any other single cause. In 2004, one in every five deathsin the United States resulted from ischemic heart disease. Indeed, thedisease has had a profound impact worldwide. If left untreated, ischemicheart disease can lead to chronic heart failure, which can be defined asa significant decrease in the heart's ability to pump blood. Chronicheart failure is often treated with drug therapy.

Ischemic heart disease is generally characterized by a diminished flowof blood to the myocardium and is also often treated using drug therapy.Although many of the available drugs may be administered systemically,local drug delivery (“LDD”) directly to the heart can result in higherlocal drug concentrations with fewer systemic side effects, therebyleading to improved therapeutic outcomes.

Cardiac drugs may be delivered locally via catheter passing through theblood vessels to the inside of the heart. However, endoluminal drugdelivery has several shortcomings, such as: (1) inconsistent delivery,(2) low efficiency of localization, and (3) relatively rapid washoutinto the circulation.

To overcome such shortcomings, drugs may be delivered directly into thepericardial space, which surrounds the external surface of the heart.The pericardial space is a cavity formed between the heart and therelatively stiff pericardial sac that encases the heart. Although thepericardial space is usually quite small because the pericardial sac andthe heart are in such close contact, a catheter may be used to inject adrug into the pericardial space for local administration to themyocardial and coronary tissues. Drug delivery methods that supply theagent to the heart via the pericardial space offer several advantagesover endoluminal delivery, including: (1) enhanced consistency and (2)prolonged exposure of the drug to the cardiac tissue.

In current practice, drugs are delivered into the pericardial spaceeither by the percutaneous transventricular method or by thetransthoracic approach. The percutaneous transventricular methodinvolves the controlled penetration of a catheter through theventricular myocardium to the pericardial space. The transthoracicapproach involves accessing the pericardial space from outside the heartusing a sheathed needle with a suction tip to grasp the pericardium,pulling it away from the myocardium to enlarge the pericardial space,and injecting the drug into the space with the needle.

For some patients with chronic heart failure, cardiac resynchronizationtherapy (“CRT”) can be used in addition to drug therapy to improve heartfunction. Such patients generally have an abnormality in conduction thatcauses the right and left ventricles to beat (i.e., begin systole) atslightly different times, which further decreases the heart'salready-limited function. CRT helps to correct this problem ofdyssynchrony by resynchronizing the ventricles, thereby leading toimproved heart function. The therapy involves the use of an implantabledevice that helps control the pacing of at least one of the ventriclesthrough the placement of electrical leads onto specified areas of theheart. Small electrical signals are then delivered to the heart throughthe leads, causing the right and left ventricles to beat simultaneously.

Like the local delivery of drugs to the heart, the placement of CRTleads on the heart can be challenging, particularly when the targetplacement site is the left ventricle. Leads can be placed using atransvenous approach through the coronary sinus, by surgical placementat the epicardium, or by using an endocardial approach. Problems withthese methods of lead placement can include placement at an improperlocation (including inadvertent placement at or near scar tissue, whichdoes not respond to the electrical signals), dissection or perforationof the coronary sinus or cardiac vein during placement, extendedfluoroscopic exposure (and the associated radiation risks) duringplacement, dislodgement of the lead after placement, and long andunpredictable times required for placement (ranging from about 30minutes to several hours).

Clinically, the only approved non-surgical means for accessing thepericardial space include the subxiphoid and the ultrasound-guidedapical and parasternal needle catheter techniques, and each methodsinvolves a transthoracic approach. In the subxiphoid method, a sheathedneedle with a suction tip is advanced from a subxiphoid position intothe mediastinum under fluoroscopic guidance. The catheter is positionedonto the anterior outer surface of the pericardial sac, and the suctiontip is used to grasp the pericardium and pull it away from the hearttissue, thereby creating additional clearance between the pericardialsac and the heart. The additional clearance tends to decrease thelikelihood that the myocardium will be inadvertently punctured when thepericardial sac is pierced.

Although this technique works well in the normal heart, there are majorlimitations in diseased or dilated hearts—the very hearts for which drugdelivery and CRT lead placement are most needed. When the heart isenlarged, the pericardial space is significantly smaller and the risk ofpuncturing the right ventricle or other cardiac structures is increased.Additionally, because the pericardium is a very stiff membrane, thesuction on the pericardium provides little deformation of thepericardium and, therefore, very little clearance of the pericardiumfrom the heart.

Thus, there is need for an efficient, easy to use, and relativelyinexpensive technique that can be used to access the heart for localdelivery of therapeutic and diagnostic substances, as well as of CRTleads and other types of leads.

BRIEF SUMMARY

Disclosed herein are devices, systems, and methods for accessing theinternal and external tissues of the heart. At least some of thedisclosed embodiments provide access to the external surface of theheart through the pericardial space for localized delivery of leads tothe heart tissue. In addition, various disclosed embodiments providedevices, systems, and methods for closing a hole or wound in cardiactissue.

For example, disclosed herein is a system for use with a vacuum sourcefor placing a lead into a tissue of a heart, comprising an engagementcatheter comprising a proximal end, a distal end, and first and secondlumens extending between the proximal end and the distal end; a deliverycatheter comprising an elongated tube having a wall and a first lumen,wherein the delivery catheter is configured such that the deliverycatheter is capable of at least partial insertion into the second lumenof the engagement catheter; a lead having a tip at a distal end, thelead configured for at least partial insertion into the first lumen ofthe delivery catheter; and a vacuum port located at the proximal end ofthe engagement catheter, the vacuum port being operatively connected tothe first lumen of the engagement catheter and capable of operativeconnection to the vacuum source; wherein the first lumen of theengagement catheter includes a suction port located at or near thedistal end of the engagement catheter, the suction port being configuredto removably attach to a targeted tissue on the interior of a wall ofthe heart, such that the suction port is capable of forming a reversibleseal with the targeted tissue when the vacuum source is operativelyattached to the vacuum port, and wherein the system is capable ofenlarging a pericardial space between the targeted tissue and apericardial sac that surrounds the heart by retracting the targetedtissue away from the pericardial sac. In at least some embodiments, thefirst lumen of the delivery catheter extends from approximately theproximal end of the tube to or near the distal end of the tube, thefirst lumen of the delivery catheter having a bend, relative to thetube, at or near the distal end of the tube and an outlet through thewall of the tube at or near the distal end of the tube. In addition, thebend of the first lumen of the delivery catheter may form an angle thatis approximately 90-degrees.

Certain disclosed embodiments of the delivery catheter disclosed hereinmay further comprise a second lumen extending from approximately theproximal end of the tube to or near the distal end of the tube, thesecond lumen of the delivery catheter having a bend, relative to thetube, at or near the distal end of the tube and an outlet through thewall of the tube at or near the distal end of the tube. The bend of thesecond lumen of the delivery catheter may form an angle that isapproximately 90-degrees.

In certain embodiments, the lead comprises a pacing lead, and the tip ofthe pacing lead has a substantially screw-like shape.

The delivery catheter may further comprise a steering channel extendingfrom a proximal end of the tube to a distal end of the tube and asteering wire system at least partially located in the steering channel.The steering wire system may comprise a first steering wire, a secondsteering wire, and a controller, each of the first and second steeringwires being attached to the wall of the tube within the steering channeland the controller being attached to a proximal end of each of the firstand second steering wires. The controller of the steering wire systemmay comprise a first handle attached to the proximal end of the firststeering wire and a second handle attached to the proximal end of thesecond steering wire.

In at least some embodiments, the controller of the steering wire systemcomprises a torque system having a first rotatable spool capable ofcollecting and dispensing the first steering wire and a second rotatablespool capable of collecting and dispensing the second steering wire.

In some embodiments, the steering wire system further comprises a thirdsteering wire; the first steering wire is attached to the wall of thetube within the steering channel at the distal end of the tube, theattachment between the first steering wire and the wall forming a firstattachment point; the second steering wire is attached to the wall ofthe tube within the steering channel at the distal end of the tube, theattachment between the second steering wire and the wall forming asecond attachment point; the third steering wire is attached to the wallof the tube within the steering channel at the distal end of the tube,the attachment between the third steering wire and the wall forming athird attachment point; and the third attachment point is closer to theproximal end of the tube than is the first attachment point or thesecond attachment point.

In some embodiments, the delivery catheter further comprises a handle ator near the proximal end of the tube; and the controller of the steeringwire system is attached to the handle.

Also disclosed herein is a delivery catheter for use in accessing apericardial space surrounding the external surface of a heart,comprising an elongated tube comprising a wall extending from a proximalend of the tube to a distal end of the tube, a first lumen, and asteering channel extending from a proximal end of the tube to a distalend of the tube, the steering channel forming an orifice at the distalend of the tube; and a steering wire system at least partially locatedin the steering channel, the steering wire system comprising at leasttwo steering wires attached to the wall of the tube within the steeringchannel and a controller attached to a proximal end of each of the atleast two steering wires; wherein the first lumen extends fromapproximately the proximal end of the tube to or near the distal end ofthe tube, the first lumen having a bend, relative to the tube, at ornear the distal end of the tube and an outlet through the wall of thetube at or near the distal end of the tube. In at least someembodiments, the steering channel of the tube and the orifice of thetube are sized for insertion over an elongated guide wire such that theelongated guide wire is inserted through the orifice and into thesteering channel. Certain embodiments further comprise a pacing leadsized for delivery through the outlet of the first lumen.

In certain embodiments, the at least two steering wires comprise a firststeering wire and a second steering wire; and the controller of thesteering wire system comprises a first handle attached to the proximalend of the first steering wire and a second handle attached to theproximal end of the second steering wire. The controller of the steeringwire system may comprise a torque system having a first rotatable spoolcapable of collecting and dispensing the first steering wire and asecond rotatable spool capable of collecting and dispensing the secondsteering wire. The first rotatable spool may be attached to a firstrotatable dial such that rotation of the first rotatable dial causesrotation of the first rotatable spool; and the second rotatable spoolmay be attached to a second rotatable dial such that rotation of thesecond rotatable dial causes rotation of the second rotatable spool. Insome embodiments, each of the at least two steering wires is attached tothe wall of the tube within the steering channel at the distal end ofthe tube.

In certain embodiments, the at least two steering wires comprise a firststeering wire, a second steering wire, and a third steering wire; andthe first steering wire is attached to the wall of the tube within thesteering channel at the distal end of the tube, the attachment betweenthe first steering wire and the wall forming a first attachment point;the second steering wire is attached to the wall of the tube within thesteering channel at the distal end of the tube, the attachment betweenthe second steering wire and the wall forming a second attachment point;the third steering wire is attached to the wall of the tube within thesteering channel at the distal end of the tube, the attachment betweenthe third steering wire and the wall forming a third attachment point;and the third attachment point is closer to the proximal end of the tubethan is the first attachment point or the second attachment point.

Some embodiments further comprise a sensing lead positioned at leastpartially within the first lumen, and some embodiments further comprisea micro-camera system positioned at least partially within the secondlumen. Further, a laser Doppler tip may be positioned at least partiallywithin the second lumen.

At least some embodiments disclosed herein include a method of placing alead in a tissue of a heart, the method comprising: extending into ablood vessel an elongated tube having a proximal end, a distal end, anda first lumen, such that the distal end of the tube is in contact with atargeted tissue on the interior of a wall of the heart; aspirating thetargeted tissue such that the wall of the heart is retracted away from apericardial sac surrounding the heart to enlarge a pericardial spacebetween the pericardial sac and the wall of the heart; accessing thepericardial space through the targeted tissue; inserting at least thedistal end of an elongated guide wire into the pericardial space;inserting into the first lumen of the elongated tube and over theelongated guide wire a delivery catheter comprising a first lumen,wherein the first lumen of the delivery catheter has a bend at or nearthe distal end of the delivery catheter and an outlet at or near thedistal end of the delivery catheter; advancing at least the distal endof the delivery catheter through the targeted tissue into thepericardial space; directing the delivery catheter such that the outletof the first lumen of the delivery catheter is adjacent to the tissue ofthe heart; extending a lead through the first lumen of the deliverycatheter into the tissue of the heart; withdrawing the delivery catheterfrom the pericardial space; and withdrawing the guide wire from thepericardial space. In some embodiments, the delivery catheter furthercomprises a steering channel and a steering wire system located at leastpartially within the steering channel; and the step of directing thedelivery catheter such that the outlet of the first lumen of thedelivery catheter is adjacent to the tissue of the heart comprisesdirecting the delivery catheter with the steering wire system. Certainembodiments may further comprise the step of extending a laser Dopplertip through a second lumen of the delivery catheter to the pericardialspace.

In some embodiments, the lead is a pacing lead; and the steering wiresystem further comprises at least two steering wires attached to thedelivery catheter inside the steering channel and a controller attachedto the proximal ends of the at least two steering wires, the controllerbeing capable of collecting and dispensing at least one of the at leasttwo steering wires.

In certain embodiments, the step of directing the delivery catheterusing the steering wire system comprises using the controller to tightenat least one of the at least two steering wires.

Certain embodiments may further comprise inserting into the targetedtissue over the guide wire a plug having a first end, a second end, anda hole extending from the first end to the second end. In someembodiments, the hole of the plug is self-sealing after removal of theguide wire.

Other embodiments disclosed herein include a system for closing a holein cardiac tissue, the system comprising an engagement cathetercomprising a proximal end, a distal end, first and second lumensextending between the proximal end and the distal end, and a vacuum portoperatively connected to the first lumen of the engagement catheter atthe proximal end of the engagement catheter, the vacuum port beingcapable of operative connection to a vacuum source, wherein the firstlumen of the engagement catheter includes a suction port located at ornear the distal end of the engagement catheter, the suction portconfigured to removably attach to a targeted tissue on the interior of awall of the heart, such that the suction port is capable of forming areversible seal with the targeted tissue when a vacuum source isoperatively attached to the vacuum port; an elongated wire capable ofinsertion into the second lumen of the engagement catheter; a plughaving a first end, a second end, and a hole extending from the firstend to the second end, the plug being capable of insertion into thesecond lumen of the engagement catheter; and an elongated shaft having aproximal end, a distal end, and a lumen extending from the proximal endto the distal end, the elongated shaft being capable of insertion intothe second lumen of the engagement catheter; wherein the elongated wireis sized for slidable insertion through the lumen of the shaft and thehole of the plug. The first end of the plug may be radiopaque. In someembodiments, the first end of the plug has a smaller diameter than thesecond end of the plug. Certain embodiments may include a plug having anexternal surface that has a screw-shaped ridge.

In some embodiments, the elongated wire comprises a lead, while in otherembodiments the elongated wire comprises an elongated guide wire.

At least some disclosed embodiments include a system for closing a holein cardiac tissue, the system comprising: an engagement cathetercomprising a proximal end, a distal end, first and second lumensextending between the proximal end and the distal end, and a vacuum portoperatively connected to the first lumen of the engagement catheter atthe proximal end of the engagement catheter, the vacuum port beingcapable of operative connection to a vacuum source, wherein the firstlumen of the engagement catheter includes a suction port located at ornear the distal end of the engagement catheter, the suction portconfigured to removably attach to a targeted tissue on the interior of awall of the heart, such that the suction port is capable of forming areversible seal with the targeted tissue when a vacuum source isoperatively attached to the vacuum port; a delivery catheter comprisinga proximal end, a distal end, and a hollow tube extending between theproximal end and the distal end, the delivery catheter configured suchthat the hollow tube is capable of insertion into the second lumen ofthe engagement catheter; an elongated delivery wire having a proximalend and a distal end, the distal end of the delivery wire being capableof insertion through the hollow tube of the delivery catheter; and aclosure member having a first face and a second face, the closure memberbeing capable of transitioning from a folded configuration within thehollow tube of the delivery catheter to an expanded configurationoutside of the hollow tube of the delivery catheter; wherein the firstface of the closure member is configured for reversible attachment tothe distal end of the delivery wire. In at least some embodiments, theclosure member comprises an external cover and an internal cover; thefirst face of the closure member comprises an outside face of theinternal cover; and the second face of the closure member comprises anoutside face of the external cover. Further, the internal cover mayfurther comprise an inside face; the external cover may further comprisean inside face; and at least one of the inside face of the internalcover and the inside face of the external cover may comprise a magnet.

In at least some embodiments, the external cover is attached to theinternal cover. In some embodiments, the internal cover furthercomprises an inside face; the external cover further comprises an insideface; and an adhesive is attached to the inside face of the internalcover and the inside face of the external cover.

The closure member may comprise a biodegradable substance. In someembodiments, the closure member comprises nitinol.

Also disclosed herein are embodiments including a method for closing ahole in a targeted tissue of a heart, the method comprising: contactingthe targeted tissue in the interior of the heart with a distal end of anelongated tube, the elongated tube having a first lumen and a secondlumen; aspirating the targeted tissue such that the targeted tissue isretracted away from a pericardial sac surrounding the heart and apericardial space between the pericardial sac and the targeted tissue isenlarged; inserting through the first lumen of the elongated tube adelivery catheter having a lumen; inserting an elongated delivery wirethrough the lumen of the delivery catheter, the elongated delivery wirehaving an external cover that is capable of transitioning from a foldedconfiguration within the lumen of the delivery catheter to an expandedconfiguration outside of the lumen of the delivery catheter, theexternal cover being reversibly attached to a distal end of the deliverywire; delivering the external cover through the hole in the targetedtissue into the pericardial space; placing the external cover onto thetargeted tissue from the pericardial space; releasing the external coverfrom the delivery wire; and withdrawing the delivery wire from thetargeted tissue. In some embodiments, the method further comprises thesteps of: reversibly attaching an internal cover to the distal end ofthe delivery wire, the internal cover being capable of transitioningfrom a folded configuration within the lumen of the delivery catheter toan expanded configuration outside of the lumen of the delivery catheter;delivering the internal cover to the targeted tissue in the interior ofthe heart; placing the internal cover onto the targeted tissue from theinterior of the heart; releasing the internal cover from the deliverywire; and withdrawing the delivery wire from the interior of the heart.

At least some embodiments include a method for closing a hole in atargeted tissue of a heart, the method comprising: providing access tothe hole in the targeted tissue by inserting a wire through a lumen ofan elongated tube and through the hole in the targeted tissue, theelongated tube having a proximal end and a distal end adjacent to thetargeted tissue; inserting into the lumen of the elongated tube and overthe wire a plug having a first end, a second end, and a hole extendingfrom the first end to the second end; inserting into the lumen of theelongated tube and over the wire an elongated shaft having a proximalend, a distal end, and a hole extending from the proximal end to thedistal end; sliding the elongated shaft toward the distal end of theelongated tube until the plug approaches the hole in the targetedtissue; inserting the plug into the hole in the targeted tissue; andwithdrawing the elongated shaft from the elongated tube. In someembodiments, the first end of the plug has a diameter that is smallerthan the diameter of the second end of the plug, and the first end ofthe plug may be radiopaque. The embodiment may further comprise the stepof confirming the location of the plug using radiographic imaging.

In at least some embodiments, the wire comprises a guide wire, and thehole of the plug closes after the guide wire is withdrawn from the holeof the plug.

Certain embodiments include a delivery catheter for use in accessing apericardial space surrounding the external surface of a heart,comprising: an elongated tube comprising a wall extending from aproximal end of the tube to a distal end of the tube, a first lumen, anda second lumen; wherein the first lumen extends from approximately theproximal end of the tube to or near the distal end of the tube, thefirst lumen having a bend, relative to the tube, at or near the distalend of the tube and an outlet through the wall of the tube at or nearthe distal end of the tube; and wherein the second lumen extends fromapproximately the proximal end of the tube to or near the distal end ofthe tube, the second lumen having a bend, relative to the tube, at ornear the distal end of the tube and an outlet through the wall of thetube at or near the distal end of the tube. The bend of the first lumenmay form an angle that is approximately 90-degrees, and the bend of thesecond lumen may form an angle that is approximately 90-degrees.

At least some embodiments further comprise a laser Doppler tippositioned at least partially within the second lumen. A needle may bepositioned at least partially within the first lumen.

Disclosed herein are embodiments including a method of injecting asubstance into a cardiac tissue from the pericardial space surroundingthe external surface of a heart, the method comprising: extending into ablood vessel an elongated tube having a proximal end, a distal end, anda first lumen, such that the distal end of the tube is in contact with atargeted tissue on the interior of a wall of the heart; aspirating thetargeted tissue such that the wall of the heart is retracted away from apericardial sac surrounding the heart to enlarge a pericardial spacebetween the pericardial sac and the wall of the heart; accessing thepericardial space through the targeted tissue; inserting at least thedistal end of an elongated guide wire into the pericardial space;inserting into the first lumen of the elongated tube and over theelongated guide wire a delivery catheter comprising a first lumen,wherein the first lumen of the delivery catheter has a bend at or nearthe distal end of the delivery catheter and an outlet at or near thedistal end of the delivery catheter; advancing at least the distal endof the delivery catheter through the targeted tissue into thepericardial space; directing the delivery catheter such that the outletof the first lumen of the delivery catheter is adjacent to the externalsurface of the heart; extending a needle through the first lumen of thedelivery catheter into the cardiac tissue; injecting the substance intothe cardiac tissue; and withdrawing the delivery catheter from thepericardial space. The substance may comprise gene cells, growthfactors, and/or a biodegradable synthetic polymer. The biodegradablesynthetic polymer may be selected from the group consisting ofpolylactides, polyglycolides, polycaprolactones, polyanhydrides,polyamides, and polyurethanes. In certain embodiments, the substancecomprises a tissue inhibitor, such as a metalloproteinase. In at leastcertain embodiments, the substance comprises RGD-liposome biologic glue.

In at least some embodiments, the delivery catheter further comprises asecond lumen, wherein the second lumen of the delivery catheter has abend at or near the distal end of the delivery catheter and an outlet ator near the distal end of the delivery catheter. The delivery cathetermay further comprise a laser Doppler tip. In some embodiments, themethod further comprises the step of measuring the thickness of thecardiac tissue using the laser Doppler tip.

Certain embodiments include a system for closing a hole in a targetedtissue, comprising: a closure member having a head and a plurality ofarms extending from the head, the closure member capable oftransitioning between an open position and a closed position; and adelivery catheter comprising a proximal end, a distal end, and a hollowtube extending between the proximal end and the distal end, the deliverycatheter configured such that the closure member is capable of insertioninto the hollow tube when the closure member is in the open position. Inat least some embodiments, the system further comprises an engagementcatheter comprising a proximal end, a distal end, a first lumenextending between the proximal end and the distal end, and a vacuum portoperatively connected to the first lumen of the engagement catheter atthe proximal end of the engagement catheter, the vacuum port beingcapable of operative connection to a vacuum source, wherein the firstlumen of the engagement catheter includes a suction port located at ornear the distal end of the engagement catheter, the suction portconfigured to removably attach to a targeted tissue on the interior of awall of the heart, such that the suction port is capable of forming areversible seal with the targeted tissue when a vacuum source isoperatively attached to the vacuum port; wherein the delivery catheteris configured for inserted into the first lumen of the engagementcatheter.

The plurality of arms of the closure member may comprise nitinol. Insome embodiments, the plurality of arms of the closure member comprisefour arms.

In at least certain embodiments, a method for closing a hole in atargeted tissue of a heart, the method comprises: providing a closuremember having a head and a plurality of arms extending from the head,the closure member capable of transitioning between an open position anda closed position; delivering the closure member to the heart through adelivery catheter comprising a proximal end, a distal end, and a hollowtube extending between the proximal end and the distal end, the deliverycatheter configured such that the closure member is capable of insertioninto the hollow tube when the closure member is in the open position;deploying the closure member such that the closure member contacts thetargeted tissue and transitions to the closed position. The step ofdelivery the closure member to the heart may comprise advancing theclosure member through the delivery catheter by pushing on the head ofthe closure member using a rod inserted into the hollow tube.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows an embodiment of an engagement catheter and an embodimentof a delivery catheter as disclosed herein;

FIG. 1B shows a percutaneous intravascular pericardial delivery usinganother embodiment of an engagement catheter and another embodiment of adelivery catheter as disclosed herein;

FIG. 2A shows a percutaneous intravascular technique for accessing thepericardial space through a right atrial wall or atrial appendage usingthe engagement and delivery catheters shown in FIG. 1A;

FIG. 2B shows the embodiment of an engagement catheter shown in FIG. 2A;

FIG. 2C shows another view of the distal end of the engagement catheterembodiment shown in FIGS. 2A and 2B;

FIG. 3A shows removal of an embodiment of a catheter as disclosedherein;

FIG. 3B shows the resealing of a puncture according to an embodiment asdisclosed herein;

FIG. 4A to 4C show a closure of a hole in the atrial wall using anembodiment as disclosed herein;

FIG. 4D shows another closure of a hole in cardiac tissue using anotherembodiment as disclosed herein;

FIG. 4E shows yet another closure of a hole in cardiac tissue usinganother embodiment as disclosed herein;

FIG. 4F shows still another closure of a hole in cardiac tissue usinganother embodiment as disclosed herein;

FIG. 5A shows an embodiment of an engagement catheter as disclosedherein;

FIG. 5B shows a cross-sectional view of the proximal end of theengagement catheter shown in FIG. 5A;

FIG. 5C shows a cross-sectional view of the distal end of the engagementcatheter shown in FIG. 5A;

FIG. 5D shows the engagement catheter shown in FIG. 5A approaching aheart wall from inside of the heart;

FIG. 6A shows an embodiment of a delivery catheter as disclosed herein;

FIG. 6B shows a close-up view of the needle shown in FIG. 6A;

FIG. 6C shows a cross-sectional view of the needle shown in FIGS. 6A and6B;

FIG. 7 shows an embodiment of a delivery catheter as disclosed herein;

FIG. 8 shows an embodiment of a steering wire system within a steeringchannel;

FIG. 9A shows another embodiment of a steering wire system as disclosedherein, the embodiment being deflected in one location;

FIG. 9B shows the steering wire system shown in FIG. 9A, wherein thesteering wire system is deflected at two locations;

FIG. 9C shows the steering wire system shown in FIGS. 9A and 9B in itsoriginal position;

FIG. 10 shows a portion of another embodiment of a steering wire system;

FIG. 11 shows a cross-sectional view of another embodiment of a deliverycatheter as disclosed herein;

FIG. 12A shows an embodiment of a system for closing a hole in cardiactissue, as disclosed herein;

FIG. 12B shows another embodiment of a system for closing a hole incardiac tissue, as disclosed herein;

FIG. 12C shows another embodiment of a system for closing a hole incardiac tissue, as disclosed herein;

FIG. 13 shows another embodiment of a system for closing a hole incardiac tissue, as disclosed herein;

FIG. 14 shows another embodiment of a system for closing a hole incardiac tissue, as disclosed herein;

FIG. 15A shows another embodiment of a system for closing a hole incardiac tissue, as disclosed herein;

FIG. 15B shows the embodiment of FIG. 15A approaching cardiac tissue;and

FIG. 15C shows the embodiment of FIGS. 15A-15C deployed on the cardiactissue.

DETAILED DESCRIPTION

It will be appreciated by those of skill in the art that the followingdetailed description of the disclosed embodiments is merely exemplary innature and is not intended to limit the scope of the appended claims.

The disclosed embodiments include devices, systems, and methods usefulfor accessing various tissues of the heart from inside the heart. Forexample, various embodiments provide for percutaneous, intravascularaccess into the pericardial space through an atrial wall or the wall ofan atrial appendage. In at least some embodiments, the heart wall isaspirated and retracted from the pericardial sac to increase thepericardial space between the heart and the sac and thereby facilitateaccess into the space.

Unlike the relatively stiff pericardial sac, the atrial wall and atrialappendage are rather soft and deformable. Hence, suction of the atrialwall or atrial appendage can provide significantly more clearance of thecardiac structure from the pericardium as compared to suction of thepericardium. Furthermore, navigation from the intravascular region(inside of the heart) provides more certainty of position of vitalcardiac structures than does intrathoracic access (outside of theheart).

Access to the pericardial space may be used for identification ofdiagnostic markers in the pericardial fluid; for pericardiocentesis; andfor administration of therapeutic factors with angiogenic, myogenic, andantiarrhythmic potential. In addition, as explained in more detailbelow, epicardial pacing leads may be delivered via the pericardialspace, and an ablation catheter may be used on the epicardial tissuefrom the pericardial space.

In the embodiment of the catheter system shown in FIG. 1A, cathetersystem 10 includes an engagement catheter 20, a delivery catheter 30,and a needle 40. Although each of engagement catheter 20, deliverycatheter 30, and needle 40 has a proximal end and a distal end, FIG. 1Ashows only the distal end. Engagement catheter 20 has a lumen throughwhich delivery catheter 30 has been inserted, and delivery catheter 30has a lumen through which needle 40 has been inserted. Delivery catheter30 also has a number of openings 50 that can be used to transmit fluidfrom the lumen of the catheter to the heart tissue in close proximity tothe distal end of the catheter.

As shown in more detail in FIGS. 2A, 2B, 2C, engagement catheter 20includes a vacuum channel 60 used for suction of a targeted tissue 65 inthe heart and an injection channel 70 used for infusion of substances totargeted tissue 65, including, for example, a biological ornon-biological degradable adhesive. As is shown in FIGS. 2B and 2C,injection channel 70 is ring-shaped, which tends to provide relativelyeven dispersal of the infused substance over the targeted tissue, butother shapes of injection channels may be suitable. A syringe 80 isattached to injection channel 70 for delivery of the appropriatesubstances to injection channel 70, and a syringe 90 is attached tovacuum channel 60 through a vacuum port (not shown) at the proximal endof engagement catheter 20 to provide appropriate suction through vacuumchannel 60. At the distal end of engagement catheter 20, a suction port95 is attached to vacuum channel 60 for contacting targeted tissue 65,such that suction port 95 surrounds targeted tissue 65, which is therebyencompassed within the circumference of suction port 95. Althoughsyringe 90 is shown in FIG. 2B as the vacuum source providing suctionfor engagement catheter 20, other types of vacuum sources may be used,such as a controlled vacuum system providing specific suction pressures.Similarly, syringe 80 serves as the external fluid source in theembodiment shown in FIG. 2B, but other external fluid sources may beused.

A route of entry for use of various embodiments disclosed herein isthrough the jugular or femoral vein to the superior or inferior venacavae, respectively, to the right atrial wall or atrial appendage(percutaneously) to the pericardial sac (through puncture).

Referring now to FIG. 1B, an engagement catheter 100 is placed viastandard approach into the jugular or femoral vein. The catheter, whichmay be 4 or 5 Fr., is positioned under fluoroscopic or echocardiographicguidance into the right atrial appendage 110. Suction is initiated toaspirate a portion of atrial appendage 110 away from the pericardial sac120 that surrounds the heart. As explained herein, aspiration of theheart tissue is evidenced when no blood can be pulled back throughengagement catheter 100 and, if suction pressure is being measured, whenthe suction pressure gradually increases. A delivery catheter 130 isthen inserted through a lumen of engagement catheter 100. A smallperforation can be made in the aspirated atrial appendage 110 with aneedle such as needle 40, as shown in FIGS. 1A and 2A. A guide wire (notshown) can then be advanced through delivery catheter 130 into thepericardial space to secure the point of entry 125 through the atrialappendage and guide further insertion of delivery catheter 130 oranother catheter. Flouroscopy or echocardiogram can be used to confirmthe position of the catheter in the pericardial space. Alternatively, apressure tip needle can sense the pressure and measure the pressurechange from the atrium (about 10 mmHg) to the pericardial space (about 2mmHg). This is particularly helpful for transeptal access where punctureof arterial structures (e.g., the aorta) can be diagnosed and sealedwith an adhesive, as described in more detail below.

Although aspiration of the atrial wall or the atrial appendage retractsthe wall or appendage from the pericardial sac to create additionalpericardial space, CO2 gas can be delivered through a catheter, such asdelivery catheter 130, into the pericardial space to create additionalspace between the pericardial sac and the heart surface.

Referring now to FIG. 3A, the catheter system shown in FIG. 1B isretrieved by pull back through the route of entry. However, the punctureof the targeted tissue in the heart (e.g., the right atrial appendage asshown in FIG. 3A) may be sealed upon withdrawal of the catheter, whichprevents bleeding into the pericardial space. The retrieval of thecatheter may be combined with a sealing of the tissue in one of severalways: (1) release of a tissue adhesive or polymer 75 via injectionchannel 70 to seal off the puncture hole, as shown in FIG. 3B; (2)release of an inner clip or mechanical stitch to close off the hole fromthe inside of the cavity or the heart, as discussed herein; or (3)mechanical closure of the heart with a sandwich type mechanical devicethat approaches the hole from both sides of the wall (see FIGS. 4A, 4B,and 4C). In other words, closure may be accomplished by using, forexample, a biodegradable adhesive material (e.g., fibrin glue orcyanomethacrylate), a magnetic system, or an umbrella-shaped nitinolstent. An example of the closure of a hole in the atrium is shown inFIG. 3B. Engagement catheter 20 is attached to targeted tissue 95 usingsuction through suction port 60. Tissue adhesive 75 is injected throughinjection channel 70 to coat and seal the puncture wound in targetedtissue 95. Engagement catheter 20 is then withdrawn, leaving a plug oftissue adhesive 75 attached to the atrial wall or atrial appendage.

Other examples for sealing the puncture wound in the atrial wall orappendage are shown in FIGS. 4A-4F. Referring now to FIGS. 4A-4C, asandwich-type closure member, having an external cover 610 and aninternal cover 620, is inserted through the lumen of engagement catheter600, which is attached to the targeted tissue of an atrial wall 630.Each of external and internal covers 610 and 620 is similar to anumbrella in that it can be inserted through a catheter in its foldedconfiguration and expanded to an expanded configuration once it isoutside of the catheter. As shown in FIG. 4A, external cover 610 isdeployed (in its expanded configuration) on the outside of the atrialwall to seal a puncture wound in the targeted tissue, having alreadybeen delivered through the puncture wound into the pericardial space.Internal cover 620 is delivered through engagement catheter 600 (in itsfolded configuration), as shown in FIGS. 4A and 4B, by an elongateddelivery wire 615, to which internal cover 620 is reversibly attached(for example, by a screw-like mechanism). Once internal cover 620 is inposition on the inside of atrial wall 630 at the targeted tissue,internal cover 620 is deployed to help seal the puncture wound in thetargeted tissue (see FIG. 4C).

Internal cover 620 and external cover 610 may be made from a number ofmaterials, including a shape-memory alloy such as nitinol. Suchembodiments are capable of existing in a catheter in a foldedconfiguration and then expanding to an expanded configuration whendeployed into the body. Such a change in configuration can result from achange in temperature, for example. Other embodiments of internal andexternal covers may be made from other biocompatible materials anddeployed mechanically.

After internal cover 620 is deployed, engagement catheter 600 releasesits grip on the targeted tissue and is withdrawn, leaving thesandwich-type closure to seal the puncture wound, as shown in FIG. 4C.External cover 610 and internal cover 620 may be held in place using abiocompatible adhesive. Similarly, external cover 610 and internal cover620 may be held in place using magnetic forces, such as, for example, bythe inside face (not shown) of external cover 610 comprising a magnet,by the inside face (not shown) of internal cover 620 comprising amagnet, or both inside faces of external cover 610 or internal cover 620comprising magnets.

In the embodiment shown in FIGS. 4A, 4B, and 4C, the closure membercomprises external cover 610 and internal cover 620. However, in atleast certain other embodiments, the closure member need not have twocovers. For example, as shown in FIG. 4D, closure member 632 is made ofonly one cover 634. Cover 634 has a first face 636 and a second face638, and first face 636 is configured for reversible attachment todistal end 642 of delivery wire 640. Closure member 632 may be made ofany suitable material, including nitinol, which is capable oftransitioning from a folded configuration to an expanded configuration.

In the embodiment shown in FIG. 4E, a closure member 1500 comprises anexternal cover 1510 and an internal cover 1520 within a deliverycatheter 1530. External cover 1510 and internal cover 1520 are attachedat a joint 1540, which may be formed, for example, by a mechanicalattachment or by a magnetic attachment. In embodiments having a magneticattachment, each of the external cover and the internal cover may have aferromagnetic component that is capable of magnetically engaging theother ferromagnetic component.

Delivery catheter 1530 is shown after insertion through hole 1555 ofatrial wall 1550. Closure member 1500 may be advanced through deliverycatheter 1530 to approach atrial wall 1550 by pushing rod 1560. Rod 1560may be reversibly attached to internal cover 1520 so that rod 1560 maybe disconnected from internal cover 1520 after closure member 1500 isproperly deployed. For example, rod 1560 may engage internal cover 1520with a screw-like tip such that rod 1560 may be easily unscrewed fromclosure member 1500 after deployment is complete. Alternatively, rod1560 may simply engage internal cover 1520 such that internal cover 1520may be pushed along the inside of delivery catheter 1530 withoutattachment between internal cover 1520 and rod 1560.

Closure member 1500 is advanced through delivery catheter 1530 untilexternal cover 1510 reaches a portion of delivery catheter 1530 adjacentto atrial wall 1550; external cover 1510 is then pushed slowly out ofdelivery catheter 1530 into the pericardial space. External cover 1510then expands and is positioned on the outer surface of atrial wall 1550.When external cover 1510 is properly positioned on atrial wall 1550,joint 1540 is approximately even with atrial wall 1550 within hole 1555.Delivery catheter 1530 is then withdrawn slowly, causing hole 1555 toclose slightly around joint 1540. As delivery catheter 1530 continues tobe withdrawn, internal cover 1520 deploys from delivery catheter 1530,thereby opening into its expanded formation. Consequently, atrial wall1550 is pinched between internal cover 1520 and external cover 1510, andhole 1555 is closed to prevent leakage of blood from the heart.

FIG. 4F shows the occlusion of a hole (not shown) in atrial wall 1600due to the sandwiching of atrial wall 1600 between an external cover1610 and an internal cover 1620. External cover 1610 is shown deployedon the outside surface of atrial wall 1600, while internal cover 1620 isdeployed on the inside surface of atrial wall 1600. As shown, rod 1640is engaged with internal cover 1620, and delivery catheter 1630 is inthe process of being withdrawn, which allows internal cover 1620 tofully deploy. Rod 1640 is then withdrawn through delivery catheter 1630.An engagement catheter (not shown) may surround delivery catheter 1650,as explained more fully herein.

Other examples for sealing a puncture wound in the cardiac tissue areshown in FIGS. 12-15. Referring now to FIG. 12A, there is shown a plug650 having a first end 652, a second end 654, and a hole 656 extendingfrom first end 652 to second end 654. Plug 650 may be made from anysuitable material, including casein, polyurethane, silicone, andpolytetrafluoroethylene. Wire 660 has been slidably inserted into hole656 of plug 650. Wire 660 may be, for example, a guide wire or a pacinglead, so long as it extends through the hole in the cardiac tissue (notshown). As shown in FIG. 12A, first end 652 is covered with a radiopaquematerial, such as barium sulfate, and is therefore radiopaque. Thisenables the clinician to view the placement of the plug in the bodyusing radiographic imaging. For example, the clinician can confirm thelocation of the plug during the procedure, enabling a safer and moreeffective procedure for the patient.

As shown in FIG. 12A, first end 652 of plug 650 has a smaller diameterthan second end 654 of plug 650. Indeed, plug 680 shown FIG. 12B andplug 684 shown in FIGS. 13 and 14 have first ends that are smaller indiameter than their respective second ends. However, not all embodimentsof plug have a first end that is smaller in diameter than the secondend. For example, plug 682 shown in FIG. 12C has a first end with adiameter that is not smaller than the diameter of the second end. Bothtypes of plug can be used to close holes in cardiac tissue.

Referring again to FIG. 12A, elongated shaft 670 has a proximal end (notshown), a distal end 672, and a lumen 674 extending from the proximalend to distal end 672. Although no catheter is shown in FIG. 12A, plug650, wire 660, and shaft 670 are configured for insertion into a lumenof a catheter (see FIG. 14), such as an embodiment of an engagementcatheter disclosed herein. Plug 650 and shaft 670 are also configured tobe inserted over wire 660 and can slide along wire 660 because each oflumen 656 of plug 650 and lumen 674 of shaft 670 is slightly larger incircumference than wire 660.

As shown in FIGS. 13 and 14, shaft 672 is used to push plug 684 alongwire 674 within elongated tube 676 to and into the hole in the targetedcardiac tissue 678. Distal end 677 of elongated tube 676 is shownattached to cardiac tissue 678, but distal end 677 need not be attachedto cardiac tissue 678 so long as distal end 677 is adjacent to cardiactissue 678. Once plug 684 is inserted into the hole, wire 674 may bewithdrawn from the hole in plug 684 and the interior of the heart (notshown) and shaft 672 is withdrawn from elongated tube 676. In someembodiments, the plug is self-sealing, meaning that the hole of the plugcloses after the wire is withdrawn. For example, the plug may be madefrom a dehydrated protein matrix, such as casein or ameroid, whichswells after soaking up fluid. After shaft 672 is withdrawn, elongatedtube 676 can be withdrawn from the heart.

It should be noted that, in some embodiments, the wire is not withdrawnfrom the hole of the plug. For example, where the wire is a pacing lead,the wire may be left within the plug so that it operatively connects tothe CRT device.

Referring now to FIG. 12B, there is shown a plug 680 that is similar toplug 684. However, plug 680 comprises external surface 681 having aridge 683 that surrounds plug 680 in a helical or screw-like shape.Ridge 683 helps to anchor plug 680 into the hole of the targeted tissue(not shown). Other embodiments of plug may include an external surfacehaving a multiplicity of ridges surrounding the plug, for example, in acircular fashion.

FIGS. 15A-15C show yet another embodiment of a closure member forclosing a hole in a tissue. Spider clip 1700 is shown within catheter1702 and comprises a head 1705 and a plurality of arms 1710, 1720, 1730,and 1740. Each of arms 1710, 1720, 1730, and 1740 is attached at itsproximal end to head 1705. Although spider clip 1700 has four arms,other embodiments of spider clip include fewer than, or more than, fourarms. For example, some embodiments of spider clip have three arms,while others have five or more arms.

Referring again to FIGS. 15A-15C, arms 1710, 1720, 1730, and 1740 may bemade from any flexible biocompatible metal that can transition betweentwo shapes, such as a shape-memory alloy (e.g., nitinol) or stainlesssteel. Spider clip 1700 is capable of transitioning between an openposition (see FIG. 15A), in which the distal ends of its arms 1710,1720, 1730, and 1740 are spaced apart, and a closed position (see FIG.15C), in which the distal ends of arms 1710, 1720, 1730, and 1740 aregathered together. For embodiments made from a shape-memory alloy, theclip can be configured to transition from the open position to theclosed position when the metal is warmed to approximately bodytemperature, such as when the clip is placed into the cardiac tissue.For embodiments made from other types of metal, such as stainless steel,the clip is configured in its closed position, but may be transitionedinto an open position when pressure is exerted on the head of the clip.Such pressure causes the arms to bulge outward, thereby causing thedistal ends of the arms to separate.

In this way, spider clip 1700 may be used to seal a wound or hole in atissue, such as a hole through the atrial wall. For example, FIG. 15Bshows spider clip 1700 engaged by rod 1750 within engagement catheter1760. As shown, engagement catheter 1760 has a bell-shaped suction port1765, which, as disclosed herein, has aspirated cardiac tissue 1770.Cardiac tissue 1770 includes a hole 1775 therethrough, and suction port1765 fits over hole 1775 so as to expose hole 1775 to spider clip 1700.

Rod 1750 pushes spider clip 1700 through engagement catheter 1760 toadvance spider clip 1700 toward cardiac tissue 1770. Rod 1750 simplyengages head 1705 by pushing against it, but in other embodiments, therod may be reversibly attached to the head using a screw-type system. Insuch embodiments, the rod may be attached and detached from the headsimply by screwing the rod into, or unscrewing the rod out of, the head,respectively.

In at least some embodiments, the spider clip is held in its openposition during advancement through the engagement catheter by thepressure exerted on the head of the clip by the rod. This pressure maybe opposed by the biasing of the legs against the engagement catheterduring advancement.

Referring to FIG. 15C, spider clip 1700 approaches cardiac tissue 1770and eventually engages cardiac tissue 1770 such that the distal end ofeach of arms 1710, 1720, 1730, and 1740 contacts cardiac tissue 1770.Rod 1750 is disengaged from spider clip 1700, and spider clip 1700transitions to its closed position, thereby drawing the distal ends ofarms 1710, 1720, 1730, and 1740 together. As the distal ends of the armsare drawn together, the distal ends grip portions of cardiac tissue1770, thereby collapsing the tissue between arms 1710, 1720, 1730, and1740 such that hole 1775 is effectively closed.

Rod 1750 is then withdrawn, and engagement catheter 1760 is disengagedfrom cardiac tissue 1770. The constriction of cardiac tissue 1770 holdshole 1775 closed so that blood does not leak through hole 1775 afterengagement catheter 1760 is removed. After a relatively short time, thebody's natural healing processes permanently close hole 1775. Spiderclip 1700 may remain in the body indefinitely.

Referring now to FIGS. 5A, 5B, 5C, and 5D, there is shown anotherembodiment of an engagement catheter as disclosed herein. Engagementcatheter 700 is an elongated tube having a proximal end 710 and a distalend 720, as well as two lumens 730, 740 extending between proximal end710 and distal end 720. Lumens 730, 740 are formed by concentric innerwall 750 and outer wall 760, as particularly shown in FIGS. 5B and 5C.At proximal end 710, engagement catheter 700 includes a vacuum port 770,which is attached to lumen 730 so that a vacuum source can be attachedto vacuum port 770 to create suction in lumen 730, thereby forming asuction channel. At distal end 720 of catheter 700, a suction port 780is attached to lumen 730 so that suction port 780 can be placed incontact with heart tissue 775 (see FIG. 5D) for aspirating the tissue,thereby forming a vacuum seal between suction port 780 and tissue 775when the vacuum source is attached and engaged. The vacuum seal enablessuction port 780 to grip, stabilize, and retract tissue 775. Forexample, attaching a suction port to an interior atrial wall using avacuum source enables the suction port to retract the atrial wall fromthe pericardial sac surrounding the heart, which enlarges thepericardial space between the atrial wall and the pericardial sac.

As shown in FIG. 5C, two internal lumen supports 810, 820 are locatedwithin lumen 730 and are attached to inner wall 750 and outer wall 760to provide support to the walls. These lumen supports divide lumen 730into two suction channels. Although internal lumen supports 810, 820extend from distal end 720 of catheter 700 along a substantial portionof the length of catheter 700, internal lumen supports 810, 820 may ormay not span the entire length of catheter 700. Indeed, as shown inFIGS. 5A, 5B, and 5C, internal lumen supports 810, 820 do not extend toproximal end 710 to ensure that the suction from the external vacuumsource is distributed relatively evenly around the circumference ofcatheter 700. Although the embodiment shown in FIG. 5C includes twointernal lumen supports, other embodiments may have just one internalsupport or even three or more such supports.

FIG. 5D shows engagement catheter 700 approaching heart tissue 775 forattachment thereto. It is important for the clinician performing theprocedure to know when the suction port has engaged the tissue of theatrial wall or the atrial appendage. For example, in reference to FIG.5D, it is clear that suction port 780 has not fully engaged tissue 775such that a seal is formed. However, because suction port 780 is notusually seen during the procedure, the clinician may determine when theproper vacuum seal between the atrial tissue and the suction port hasbeen made by monitoring the amount of blood that is aspirated, bymonitoring the suction pressure with a pressure sensor/regulator, orboth. For example, as engagement catheter 700 approaches the atrial walltissue (such as tissue 775) and is approximately in position, thesuction can be activated through lumen 730. A certain level of suction(e.g., 10 mmHg) can be imposed and measured with a pressuresensor/regulator. As long as catheter 700 does not engage the wall, someblood will be aspirated into the catheter and the suction pressure willremain the same. However, when catheter 700 engages or attaches to thewall of the heart (depicted as tissue 775 in FIG. 5D), minimal blood isaspirated and the suction pressure will start to gradually increase.Each of these signs can alert the clinician (through alarm or othermeans) as an indication of engagement. The pressure regulator is thenable to maintain the suction pressure at a preset value to preventover-suction of the tissue.

An engagement catheter, such as engagement catheter 700, may beconfigured to deliver a fluid or other substance to tissue on the insideof a wall of the heart, including an atrial wall or a ventricle wall.For example, lumen 740 shown in FIGS. 5A and 5C includes an injectionchannel 790 at distal end 720. Injection channel 790 dispenses to thetargeted tissue a substance flowing through lumen 740. As shown in FIG.5D, injection channel 790 is the distal end of lumen 740. However, inother embodiments, the injection channel may be ring-shaped (see FIG.2C) or have some other suitable configuration.

Substances that can be locally administered with an engagement catheterinclude preparations for gene or cell therapy, drugs, and adhesives thatare safe for use in the heart. The proximal end of lumen 740 has a fluidport 800, which is capable of attachment to an external fluid source forsupply of the fluid to be delivered to the targeted tissue. Indeed,after withdrawal of a needle from the targeted tissue, as discussedherein, an adhesive may be administered to the targeted tissue by theengagement catheter for sealing the puncture wound left by the needlewithdrawn from the targeted tissue.

Referring now to FIGS. 6A, 6B, and 6C, there is shown a deliverycatheter 850 comprising an elongated hollow tube 880 having a proximalend 860, a distal end 870, and a lumen 885 along the length of thecatheter. Extending from distal end 870 is a hollow needle 890 incommunication with lumen 885. Needle 890 is attached to distal end 870in the embodiment of FIGS. 6A, 6B, and 6C, but, in other embodiments,the needle may be removably attached to, or otherwise located at, thedistal end of the catheter (see FIG. 1A). In the embodiment shown inFIGS. 6A, 6B, and 6C, as in certain other embodiments having an attachedneedle, the junction (i.e., site of attachment) between hollow tube 880and needle 890 forms a security notch 910 circumferentially aroundneedle 890 to prevent needle 890 from over-perforation. Thus, when aclinician inserts needle 890 through an atrial wall to gain access tothe pericardial space, the clinician will not, under normal conditions,unintentionally perforate the pericardial sac with needle 890 becausethe larger diameter of hollow tube 880 (as compared to that of needle890) at security notch 910 hinders further needle insertion. Althoughsecurity notch 910 is formed by the junction of hollow tube 880 andneedle 890 in the embodiment shown in FIGS. 6A, 6B, and 6C, otherembodiments may have a security notch that is configured differently.For example, a security notch may include a band, ring, or similardevice that is attached to the needle a suitable distance from the tipof the needle. Like security notch 910, other security notch embodimentshinder insertion of the needle past the notch itself by presenting alarger profile than the profile of the needle such that the notch doesnot easily enter the hole in the tissue caused by entry of the needle.

It is useful for the clinician performing the procedure to know when theneedle has punctured the atrial tissue. This can be done in severalways. For example, the delivery catheter can be connected to a pressuretransducer to measure pressure at the tip of the needle. Because thepressure is lower and much less pulsatile in the pericardial space thanin the atrium, the clinician can recognize immediately when the needlepasses through the atrial tissue into the pericardial space.

Alternatively, as shown in FIG. 6B, needle 890 may be connected to astrain gauge 915 as part of the catheter assembly. When needle 890contacts tissue (not shown), needle 890 will be deformed. Thedeformation will be transmitted to strain gauge 915 and an electricalsignal will reflect the deformation (through a classical wheatstonebridge), thereby alerting the clinician. Such confirmation of thepuncture of the wall can prevent over-puncture and can provideadditional control of the procedure.

In some embodiments, a delivery catheter, such as catheter 850 shown inFIGS. 6A, 6B, and 6C, is used with an engagement catheter, such ascatheter 700 shown in FIGS. 5A, 5B, 5C, and 5D, to gain access to thepericardial space between the heart wall and the pericardial sac. Forexample, engagement catheter 700 may be inserted into the vascularsystem and advanced such that the distal end of the engagement catheteris within the atrium. The engagement catheter may be attached to thetargeted tissue on the interior of a wall of the atrium using a suctionport as disclosed herein. A standard guide wire may be inserted throughthe lumen of the delivery catheter as the delivery catheter is insertedthrough the inner lumen of the engagement catheter, such as lumen 740shown in FIGS. 5B and 5C. Use of the guide wire enables more effectivenavigation of the delivery catheter 850 and prevents the needle 890 fromdamaging the inner wall 750 of the engagement catheter 700. When the tipof the delivery catheter with the protruding guide wire reaches theatrium, the wire is pulled back, and the needle is pushed forward toperforate the targeted tissue. The guide wire is then advanced throughthe perforation into the pericardial space, providing access to thepericardial space through the atrial wall.

Referring again to FIGS. 6A, 6B, and 6C, lumen 885 of delivery catheter850 may be used for delivering fluid into the pericardial space afterneedle 890 is inserted through the atrial wall or the atrial appendage.After puncture of the wall or appendage, a guide wire (not shown) may beinserted through needle lumen 900 into the pericardial space to maintainaccess through the atrial wall or appendage. Fluid may then beintroduced to the pericardial space in a number of ways. For example,after the needle punctures the atrial wall or appendage, the needle isgenerally withdrawn. If the needle is permanently attached to thedelivery catheter, as in the embodiment shown in FIGS. 6A and 6B, thendelivery catheter 850 would be withdrawn and another delivery catheter(without an attached needle) would be introduced over the guide wireinto the pericardial space. Fluid may then be introduced into thepericardial space through the lumen of the second delivery catheter.

In some embodiments, however, only a single delivery catheter is used.In such embodiments, the needle is not attached to the deliverycatheter, but instead may be a needle wire (see FIG. 1A). In suchembodiments, the needle is withdrawn through the lumen of the deliverycatheter, and the delivery catheter may be inserted over the guide wireinto the pericardial space. Fluid is then introduced into thepericardial space through the lumen of the delivery catheter.

The various embodiments disclosed herein may be used by clinicians, forexample: (1) to deliver genes, cells, drugs, etc.; (2) to providecatheter access for epicardial stimulation; (3) to evacuate fluidsacutely (e.g., in cases of pericardial tampondae) or chronically (e.g.,to alleviate effusion caused by chronic renal disease, cancer, etc.);(4) to perform transeptal puncture and delivery of a catheter throughthe left atrial appendage for electrophysiological therapy, biopsy,etc.; (5) to deliver a magnetic glue or ring through the right atrialappendage to the aortic root to hold a percutaneous aortic valve inplace; (6) to deliver a catheter for tissue ablation, e.g., to thepulmonary veins, or right atrial and epicardial surface of the heart foratrial and ventricular arrythmias; (7) to deliver and place epicardial,right atrial, and right and left ventricle pacing leads (as discussedherein); (8) to occlude the left atrial appendage through percutaneousapproach; and (9) to visualize the pericardial space with endo-camera orscope to navigate the epicardial surface of the heart for therapeuticdelivery, diagnosis, lead placement, mapping, etc. Many otherapplications, not explicitly listed here, are also possible and withinthe scope of the present disclosure.

Referring now to FIG. 7, there is shown a delivery catheter 1000.Delivery catheter 1000 includes an elongated tube 1010 having a wall1020 extending from a proximal end (not shown) of tube 1010 to a distalend 1025 of tube 1010. Tube 1010 includes two lumens, but otherembodiments of delivery catheters may have fewer than, or more than, twolumens, depending on the intended use of the delivery catheter. Tube1010 also includes a steering channel 1030, in which a portion ofsteering wire system 1040 is located. Steering channel 1030 formsorifice 1044 at distal end 1025 of tube 1010 and is sized to fit over aguide wire 1050.

FIG. 8 shows in more detail steering wire system 1040 within steeringchannel 1030 (which is shown cut away from the remainder of the deliverycatheter). Steering wire system 1040 is partially located in steeringchannel 1030 and comprises two steering wires 1060 and 1070 and acontroller 1080, which, in the embodiment shown in FIG. 8, comprises afirst handle 1090 and a second handle 1094. First handle 1090 isattached to proximal end 1064 of steering wire 1060, and second handle1094 is attached to proximal end 1074 of steering wire 1070. Distal end1066 of steering wire 1060 is attached to the wall of the tube of thedelivery catheter within steering channel 1030 at attachment 1100, anddistal end 1076 of steering wire 1070 is attached to the wall of thetube of the delivery catheter within steering channel 1030 at attachment1110. As shown in FIG. 7, attachment 1100 and attachment 1110 arelocated on opposing sides of steering channel 1030 near distal tip 1120of delivery catheter 1000.

In the embodiment of FIG. 8, steering wires 1060 and 1070 are threadedas a group through steering channel 1030. However, the steering wiresystems of other embodiments may include steering wires that areindividually threaded through smaller lumens within the steeringchannel. For example, FIG. 11 shows a cross-sectional view of a deliverycatheter 1260 having an elongated tube 1264 comprising a wall 1266, asteering channel 1290, a first lumen 1270, and a second lumen 1280.Delivery catheter 1260 further includes a steering wire 1292 within asteering wire lumen 1293, a steering wire 1294 within a steering wirelumen 1295, and a steering wire 1296 within a steering wire lumen 1297.Each of steering wire lumens 1293, 1295, and 1297 is located withinsteering channel 1290 and is formed from wall 1266. Each of steeringwires 1292, 1294, and 1296 is attached to wall 1266 within steeringchannel 1290. As will be explained, the attachment of each steering wireto the wall may be located near the distal tip of the delivery catheter,or may be located closer to the middle of the delivery catheter.

Referring now to FIGS. 7 and 8, steering wire system 1040 can be used tocontrol distal tip 1120 of delivery catheter 1000. For example, whenfirst handle 1090 is pulled, steering wire 1060 pulls distal tip 1120,which bends delivery catheter 1000, causing tip deflection in a firstdirection. Similarly, when second handle 1094 is pulled, steering wire1070 pulls distal tip 1120 in the opposite direction, which bendsdelivery catheter 1000, causing tip deflection in the oppositedirection. Thus, delivery catheter 1000 can be directed (i.e., steered)through the body using steering wire system 1040.

Although steering wire system 1040 has only two steering wires, otherembodiments of steering wire systems may have more than two steeringwires. For example, some embodiments of steering wire systems may havethree steering wires (see FIG. 11), each of which is attached to thesteering channel at a different attachment. Other embodiments ofsteering wire systems may have four steering wires. Generally, moresteering wires give the clinician more control for directing thedelivery catheter because each additional steering wire enables the userto deflect the tip of the delivery catheter in an additional direction.For example, four steering wires could be used to direct the deliverycatheter in four different directions (e.g., up, down, right, and left).

If a steering wire system includes more than two steering wires, thedelivery catheter may be deflected at different points in the samedirection. For instance, a delivery catheter with three steering wiresmay include two steering wires for deflection in a certain direction anda third steering wire for reverse deflection (i.e., deflection in theopposite direction). In such an embodiment, the two steering wires fordeflection are attached at different locations along the length of thedelivery catheter. Referring now to FIGS. 9A-9C, there is shown asteering wire system 1350 within steering channel 1360 (which is showncut away from the remainder of the delivery catheter) in differentstates of deflection. Steering wire system 1350 is partially located insteering channel 1360 and comprises three steering wires 1370, 1380, and1390 and a controller 1400, which, in the embodiment shown in FIGS.9A-9C, comprises a handle 1405. Handle 1405 is attached to proximal end1374 of steering wire 1370, proximal end 1384 of steering wire 1380, andproximal end 1394 of steering wire 1390. Distal end 1376 of steeringwire 1370 is attached to the wall of the tube of the delivery catheterwithin steering channel 1360 at attachment 1378, which is near thedistal tip of the delivery catheter (not shown). Distal end 1386 ofsteering wire 1380 is attached to the wall of the tube of the deliverycatheter within steering channel 1360 at attachment 1388, which is nearthe distal tip of the delivery catheter (not shown). Attachment 1378 andattachment 1388 are located on opposing sides of steering channel 1360such that steering wires 1370 and 1380, when tightened (as explainedbelow), would tend to deflect the delivery catheter in oppositedirections. Distal end 1396 of steering wire 1390 is attached to thewall of the tube of the delivery catheter within steering channel 1360at attachment 1398, which is located on the delivery catheter at a pointcloser to the proximal end of the delivery catheter than attachments1378 and 1388. Attachment 1398 is located on the same side of steeringchannel 1360 as attachment 1388, such that steering wires 1380 and 1390,when tightened (as explained below), would tend to deflect the deliverycatheter in the same direction. However, because attachment 1398 iscloser to the proximal end of the delivery catheter than is attachment1388, the tightening of steering wire 1390 tends to deflect the deliverycatheter at a point closer to the proximal end of the delivery catheterthan does the tightening of steering wire 1380. Thus, as shown in FIG.9A, the tightening of steering wire 1390 causes a deflection in thedelivery catheter approximately at point 1410. The tightening ofsteering wire 1380 at the same time causes a further deflection in thedelivery catheter approximately at point 1420, as shown in FIG. 9B. Thetightening of steering wire 1370, therefore, causes a reversedeflection, returning the delivery catheter to its original position(see FIG. 9C).

Referring again to FIG. 7, elongated tube 1010 further includes lumen1130 and lumen 1140. Lumen 1130 extends from approximately the proximalend (not shown) of tube 1010 to or near distal end 1025 of tube 1010.Lumen 1130 has a bend 1134, relative to tube 1010, at or near distal end1025 of tube 1010 and an outlet 1136 through wall 1020 of tube 1010 ator near distal end 1025 of tube 1010. Similarly, lumen 1140 has a bend1144, relative to tube 1010, at or near distal end 1025 of tube 1010 andan outlet 1146 through wall 1020 of tube 1010 at or near distal end 1025of tube 1010. In the embodiment shown in FIG. 7, lumen 1130 isconfigured as a laser Doppler tip, and lumen 1140 is sized to accept aretractable sensing lead 1150 and a pacing lead 1160 having a tip at thedistal end of the lead. The fiberoptic laser Doppler tip detects andmeasures blood flow (by measuring the change in wavelength of lightemitted by the tip), which helps the clinician to identify—and thenavoid—blood vessels during lead placement. Sensing lead 1150 is designedto detect electrical signals in the heart tissue so that the cliniciancan avoid placing a pacing lead into electrically nonresponsive tissue,such as scar tissue. Pacing lead 1160 is a screw-type lead for placementonto the cardiac tissue, and its tip, which is an electrode, has asubstantially screw-like shape. Pacing lead 1160 is capable of operativeattachment to a CRT device (not shown) for heart pacing. Although lead1160 is used for cardiac pacing, any suitable types of leads may be usedwith the delivery catheters described herein, including sensing leads.

Each of bend 1134 of lumen 1130 and bend 1144 of lumen 1140 forms anapproximately 90-degree angle, which allows respective outlets 1136 and1146 to face the external surface of the heart as the catheter ismaneuvered in the pericardial space. However, other embodiments may havebends forming other angles, smaller or larger than 90-degrees, so longas the lumen provides proper access to the external surface of the heartfrom the pericardial space. Such angles may range, for example, fromabout 25-degrees to about 155-degrees. In addition to delivering leadsand Doppler tips, lumen 1130 and lumen 1140 may be configured to allow,for example, the taking of a cardiac biopsy, the delivery of gene celltreatment or pharmacological agents, the delivery of biological glue forventricular reinforcement, implementation of ventricular epicardialsuction in the acute myocardial infarction and border zone area, theremoval of fluid in treatment of pericardial effusion or cardiactamponade, or the ablation of cardiac tissue in treatment of atrialfibrillation.

For example, lumen 1130 could be used to deliver a catheter needle forintramyocardial injection of gene cells, stems, biomaterials, growthfactors (such as cytokinase, fibroblast growth factor, or vascularendothelial growth factor) and/or biodegradable synthetic polymers,RGD-liposome biologic glue, or any other suitable drug or substance fortreatment or diagnosis. For example, suitable biodegradable syntheticpolymer may include polylactides, polyglycolides, polycaprolactones,polyanhydrides, polyamides, and polyurethanes. In certain embodiments,the substance comprises a tissue inhibitor, such as a metalloproteinase(e.g., metalloproteinase 1).

The injection of certain substances (such as biopolymers andRGD-liposome biologic glue) is useful in the treatment of chronic heartfailure to reinforce and strengthen the left ventricular wall. Thus,using the embodiments disclosed herein, the injection of such substancesinto the cardiac tissue from the pericardial space alleviates theproblems and risks associated with delivery via the transthoracicapproach. For instance, once the distal end of the delivery catheter isadvanced to the pericardial space, as disclosed herein, a needle isextended through a lumen of the delivery catheter into the cardiactissue and the substance is injected through the needle into the cardiactissue.

The delivery of substances into the cardiac tissue from the pericardialspace can be facilitated using a laser Doppler tip. For example, whentreating ventricular wall thinning, the laser Doppler tip located inlumen 1140 of the embodiment shown in FIG. 7 can be used to measure thethickness of the left ventricular wall during the procedure (in realtime) to determine the appropriate target area for injection.

Referring again to FIG. 8, although controller 1080 comprises firsthandle 1090 and second handle 1094, other embodiments of the controllermay include different configurations. For example, instead of usinghandles, a controller may include any suitable torque system forcontrolling the steering wires of the steering wire system. Referringnow to FIG. 10, there is shown a portion of a steering wire system 1170having steering wire 1180, steering wire 1190, and controller 1200.Controller 1200 comprises a torque system 1210 having a first rotatablespool 1220, which is capable of collecting and dispensing steering wire1180 upon rotation. For example, when first rotatable spool 1220 rotatesin a certain direction, steering wire 1180 is collected onto spool 1220,thereby tightening steering wire 1180. When spool 1220 rotates in theopposite direction, steering wire 1180 is dispensed from spool 1220,thereby loosening steering wire 1180. Torque system 1210 also has asecond rotatable spool 1230, which is capable of collecting anddispensing steering wire 1190 upon rotation, as described above.

Torque system 1210 further includes a first rotatable dial 1240 and asecond rotatable dial 1250. First rotatable dial 1240 is attached tofirst rotatable spool 1220 such that rotation of first rotatable dial1240 causes rotation of first rotatable spool 1220. Similarly, secondrotatable dial 1250 is attached to second rotatable spool 1230 such thatrotation of second rotatable dial 1250 causes rotation of secondrotatable spool 1230. For ease of manipulation of the catheter, torquesystem 1210, and specifically first and second rotatable dials 1240 and1250, may optionally be positioned on a catheter handle (not shown) atthe proximal end of tube 1010.

Steering wire system 1170 can be used to direct a delivery catheterthrough the body in a similar fashion as steering wire system 1140.Thus, for example, when first rotatable dial 1240 is rotated in a firstdirection (e.g., clockwise), steering wire 1180 is tightened and thedelivery catheter is deflected in a certain direction. When firstrotatable dial 1240 is rotated in the other direction (e.g.,counterclockwise), steering wire 1180 is loosened and the deliverycatheter straightens to its original position. When second rotatabledial 1250 is rotated in one direction (e.g., counterclockwise), steeringwire 1190 is tightened and the delivery catheter is deflected in adirection opposite of the first deflection. When second rotatable dial1250 is rotated in the other direction (e.g., clockwise), steering wire1190 is loosened and the delivery catheter is straightened to itsoriginal position.

Certain other embodiments of steering wire system may comprise othertypes of torque system, so long as the torque system permits theclinician to reliably tighten and loosen the various steering wires. Themagnitude of tightening and loosening of each steering wire should becontrollable by the torque system.

Referring again to FIG. 11, there is shown a cross-sectional view ofdelivery catheter 1260. Delivery catheter 1260 includes tube 1265, afirst lumen 1270, a second lumen 1280, and a steering channel 1290.Steering wires 1292, 1294, and 1296 are shown within steering channel1290. First lumen 1270 has outlet 1275, which can be used to deliver amicro-camera system (not shown) or a laser Doppler tip 1278. Secondlumen 1280 is sized to deliver a pacing lead 1300, as well as a sensinglead (not shown).

A pacing lead may be placed on the external surface of the heart usingan engagement catheter and a delivery catheter as disclosed herein. Forexample, an elongated tube of an engagement catheter is extended into ablood vessel so that the distal end of the tube is in contact with atargeted tissue on the interior of a wall of the heart. As explainedabove, the targeted tissue may be on the interior of the atrial wall orthe atrial appendage. Suction is initiated to aspirate a portion of thetargeted tissue to retract the cardiac wall away from the pericardialsac that surrounds the heart, thereby enlarging a pericardial spacebetween the pericardial sac and the cardiac wall. A needle is theninserted through a lumen of the tube and advanced to the heart. Theneedle is inserted into the targeted tissue, causing a perforation ofthe targeted tissue. The distal end of a guide wire is inserted throughthe needle into the pericardial space to secure the point of entrythrough the cardiac wall. The needle is then withdrawn from the targetedtissue.

A delivery catheter, as described herein, is inserted into the lumen ofthe tube of the engagement catheter and over the guide wire. Thedelivery catheter may be a 14 Fr. radiopaque steering catheter. Thedistal end of the delivery catheter is advanced over the guide wirethrough the targeted tissue into the pericardial space. Once in thepericardial space, the delivery catheter is directed using a steeringwire system as disclosed herein. In addition, a micro-camera system maybe extended through the lumen of the delivery catheter to assist in thedirection of the delivery catheter to the desired location in thepericardial space. Micro-camera systems suitable for use with thedelivery catheter are well-known in the art. Further, a laser Dopplersystem may be extended through the lumen of the delivery catheter toassist in the direction of the delivery catheter. The delivery catheteris positioned such that the outlet of one of the lumens of the deliverycatheter is adjacent to the external surface of the heart (e.g., theexternal surface of an atrium or a ventricle). A pacing lead is extendedthrough the lumen of the delivery catheter onto the external surface ofthe heart. The pacing lead may be attached to the external surface ofthe heart, for example, by screwing the lead into the cardiac tissue. Inaddition, the pacing lead may be placed deeper into the cardiac tissue,for example in the subendocardial tissue, by screwing the lead furtherinto the tissue. After the lead is placed in the proper position, thedelivery catheter is withdrawn from the pericardial space and the body.The guide wire is withdrawn from the pericardial space and the body, andthe engagement catheter is withdrawn from the body.

The disclosed embodiments can be used for subendocardial, as well asepicardial, pacing. While the placement of the leads is epicardial, theleads can be configured to have a long screw-like tip that reaches nearthe subendocardial wall. The tip of the lead can be made to beconducting and stimulatory to provide the pacing to the subendocardialregion. In general, the lead length can be selected to pace transmurallyat any site through the thickness of the heart wall. Those of skill inthe art can decide whether epicardial, subendocardial, or sometransmural location stimulation of the muscle is best for the patient inquestion.

While various embodiments of devices, systems, and methods for accessingthe heart tissue have been described in considerable detail herein, theembodiments are merely offered by way of non-limiting examples of theinvention described herein. Many variations and modifications of theembodiments described herein will be apparent to one of ordinary skillin the art in light of this disclosure. It will therefore be understoodby those skilled in the art that various changes and modifications maybe made, and equivalents may be substituted for elements thereof,without departing from the scope of the invention. Indeed, thisdisclosure is not intended to be exhaustive or to limit the scope of theinvention. The scope of the invention is to be defined by the appendedclaims, and by their equivalents.

Further, in describing representative embodiments, the disclosure mayhave presented a method and/or process as a particular sequence ofsteps. However, to the extent that the method or process does not relyon the particular order of steps set forth herein, the method or processshould not be limited to the particular sequence of steps described. Asone of ordinary skill in the art would appreciate, other sequences ofsteps may be possible. Therefore, the particular order of the stepsdisclosed herein should not be construed as limitations on the claims.In addition, the claims directed to a method and/or process should notbe limited to the performance of their steps in the order written, andone skilled in the art can readily appreciate that the sequences may bevaried and still remain within the spirit and scope of the presentinvention.

It is therefore intended that the invention will include, and thisdescription and the appended claims will encompass, all modificationsand changes apparent to those of ordinary skill in the art based on thisdisclosure.

1. A system for use with a vacuum source for placing a lead into atissue of a heart, comprising: an engagement catheter comprising aproximal end, a distal end, and first and second lumens extendingbetween the proximal end and the distal end; a delivery cathetercomprising an elongated tube having a wall and a first lumen, whereinthe delivery catheter is configured such that the delivery catheter iscapable of at least partial insertion into the second lumen of theengagement catheter; a lead having a tip at a distal end, the leadconfigured for at least partial insertion into the first lumen of thedelivery catheter; and a vacuum port located at the proximal end of theengagement catheter, the vacuum port being operatively connected to thefirst lumen of the engagement catheter and capable of operativeconnection to a vacuum source; wherein the first lumen of the engagementcatheter includes a suction port located at or near the distal end ofthe engagement catheter, the suction port being configured to removablyattach to a targeted tissue on an interior of a wall of a heart afterthe engagement catheter has been advanced through a blood vessel intothe heart, such that the suction port is capable of forming a reversibleseal with the targeted tissue when the vacuum source is operativelyattached to the vacuum port.
 2. The system of claim 1, wherein: thefirst lumen of the delivery catheter extends from approximately theproximal end of the tube to or near the distal end of the tube, thefirst lumen of the delivery catheter having a bend, relative to thetube, at or near the distal end of the tube and an outlet through thewall of the tube at or near the distal end of the tube.
 3. The system ofclaim 2, wherein: the bend of the first lumen of the delivery catheterforms an angle that is approximately 90-degrees.
 4. The system of claim2, wherein: the delivery catheter further comprises a second lumenextending from approximately the proximal end of the tube to or near thedistal end of the tube, the second lumen of the delivery catheter havinga bend, relative to the tube, at or near the distal end of the tube andan outlet through the wall of the tube at or near the distal end of thetube.
 5. The system of claim 4, wherein: the bend of the first lumen ofthe delivery catheter forms an angle that is approximately 90-degrees,wherein the bend of the first lumen facilitates delivery of the lead toan external surface of the heart when at least part of the deliverycatheter is positioned within a pericardial space; and the bend of thesecond lumen of the delivery catheter forms an angle that isapproximately 90-degrees.
 6. The system of claim 2, wherein: the leadcomprises a pacing lead; and the tip of the pacing lead has asubstantially screw-like shape.
 7. The system of claim 1, wherein: thedelivery catheter further comprises a steering channel extending from aproximal end of the tube to a distal end of the tube and a steering wiresystem at least partially located in the steering channel; and thesteering wire system comprises a first steering wire, a second steeringwire, and a controller, each of the first and second steering wiresbeing attached to the wall of the tube within the steering channel andthe controller being attached to a proximal end of each of the first andsecond steering wires.
 8. The system of claim 7, wherein: the controllerof the steering wire system comprises a first handle attached to theproximal end of the first steering wire and a second handle attached tothe proximal end of the second steering wire.
 9. The system of claim 7,wherein: the controller of the steering wire system comprises a torquesystem having a first rotatable spool capable of collecting anddispensing the first steering wire and a second rotatable spool capableof collecting and dispensing the second steering wire.
 10. The system ofclaim 7, wherein: the steering wire system further comprises a thirdsteering wire; the first steering wire is attached to the wall of thetube within the steering channel at the distal end of the tube, theattachment between the first steering wire and the wall forming a firstattachment point; the second steering wire is attached to the wall ofthe tube within the steering channel at the distal end of the tube, theattachment between the second steering wire and the wall forming asecond attachment point; the third steering wire is attached to the wallof the tube within the steering channel at the distal end of the tube,the attachment between the third steering wire and the wall forming athird attachment point; and the third attachment point is closer to theproximal end of the tube than is the first attachment point or thesecond attachment point.
 11. The system of claim 7, wherein: thedelivery catheter further comprises a handle at or near the proximal endof the tube; and the controller of the steering wire system is attachedto the handle.
 12. A method of placing a lead in a tissue of a heart,the method comprising: extending into a blood vessel an elongated tubehaving a proximal end, a distal end, and a first lumen, such that thedistal end of the tube is in contact with a targeted tissue on aninterior of a wall of a heart; aspirating the targeted tissue such thatthe wall of the heart is retracted away from a pericardial sacsurrounding the heart to enlarge a pericardial space between thepericardial sac and the wall of the heart; accessing the pericardialspace through the targeted tissue; inserting into the first lumen of theelongated tube and over an elongated guide wire a delivery cathetercomprising a first lumen, wherein the first lumen of the deliverycatheter has a bend at or near the distal end of the delivery catheterto facilitate delivery of a lead into a tissue of the heart when atleast part of the delivery catheter is positioned within the pericardialspace and an outlet at or near the distal end of the delivery catheter;advancing at least the distal end of the delivery catheter through thetargeted tissue into the pericardial space; directing the deliverycatheter such that the outlet of the first lumen of the deliverycatheter is adjacent to the tissue of the heart; and extending a leadthrough the first lumen of the delivery catheter into the tissue of theheart.
 13. The method of claim 12, wherein: the delivery catheterfurther comprises a steering channel and a steering wire system locatedat least partially within the steering channel; and the step ofdirecting the delivery catheter such that the outlet of the first lumenof the delivery catheter is adjacent to the tissue of the heartcomprises directing the delivery catheter with the steering wire system.14. The method of claim 13, further comprising: extending a laserDoppler tip through a second lumen of the delivery catheter to thepericardial space.
 15. The method of claim 13, wherein: the lead is apacing lead; and the steering wire system further comprises at least twosteering wires attached to the delivery catheter inside the steeringchannel and a controller attached to the proximal ends of the at leasttwo steering wires, the controller being capable of collecting anddispensing at least one of the at least two steering wires.
 16. Themethod of claim 15, wherein: the step of directing the delivery catheterusing the steering wire system comprises using the controller to tightenat least one of the at least two steering wires.
 17. The method of claim16, further comprising: inserting into the targeted tissue over theelongated guide wire a plug having a first end, a second end, and a holeextending from the first end to the second end, wherein the hole of theplug is self-sealing after removal of the guide wire.
 18. A method ofinjecting a substance into a cardiac tissue from the pericardial spacesurrounding the external surface of a heart, the method comprising:extending into a blood vessel an elongated tube having a proximal end, adistal end, and a first lumen, such that the distal end of the tube isin contact with a targeted tissue on an interior of a wall of a heart;aspirating the targeted tissue such that the wall of the heart isretracted away from a pericardial sac surrounding the heart to enlarge apericardial space between the pericardial sac and the wall of the heart;accessing the pericardial space through the targeted tissue; insertingat least the distal end of an elongated guide wire into the pericardialspace; inserting into the first lumen of the elongated tube and over theelongated guide wire a delivery catheter comprising a first lumen,wherein the first lumen of the delivery catheter has a bend at or nearthe distal end of the delivery catheter to facilitate injection of asubstance into a cardiac tissue when at least part of the deliverycatheter is positioned within the pericardial space and an outlet at ornear the distal end of the delivery catheter; advancing at least thedistal end of the delivery catheter through the targeted tissue into thepericardial space; directing the delivery catheter such that the outletof the first lumen of the delivery catheter is adjacent to the externalsurface of the heart; extending a needle through the first lumen of thedelivery catheter into the cardiac tissue; and injecting the substanceinto the cardiac tissue.
 19. The method of claim 18, wherein: thesubstance is selected from the group consisting of gene cells, growthfactors, a biodegradable synthetic polymer, a tissue inhibitor, ametalloproteinase, and RGD-liposome biologic glue.
 20. The method ofclaim 18, wherein: the substance comprises a biodegradable syntheticpolymer selected from the group consisting of polylactides,polyglycolides, polycaprolactones, polyanhydrides, polyamides, andpolyurethanes.
 21. The method of claim 18, wherein: the substancecomprises a tissue inhibitor comprising a metalloproteinase.
 22. Themethod of claim 18, wherein: the delivery catheter further comprises asecond lumen, wherein the second lumen of the delivery catheter has abend at or near the distal end of the delivery catheter and an outlet ator near the distal end of the delivery catheter.
 23. The method of claim22, wherein: the delivery catheter further comprises a laser Dopplertip.
 24. The method of claim 23, further comprising the step of:measuring the thickness of the cardiac tissue using the laser Dopplertip.
 25. The system of claim 1, wherein the system is capable ofenlarging a pericardial space between the targeted tissue and apericardial sac that surrounds the heart by retracting the targetedtissue away from the pericardial sac.